Two out of three wild poliovirus strains eradicated

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In an historic announcement on World Polio Day, an independent commission of experts- the Global Commission for the Certification of Poliomyelitis Eradication (GCEPE) concluded that wild poliovirus type 3 (WPV3) has been eradicated worldwide. Following the eradication of smallpox and wild poliovirus type 2, this news represents a historic achievement for humanity.

Three types of wild poliovirus

There are three individual and immunologically-distinct wild poliovirus strains: wild poliovirus type 1 (WPV1), wild poliovirus type 2 (WPV2) and wild poliovirus type 3 (WPV3). Symptomatically, all three strains are identical, in that they cause irreversible paralysis or even death. But there are genetic and virologic differences which make these three strains three separate viruses that must each be eradicated individually.

WPV3 is the second strain of the poliovirus to be wiped out, following the certification of the eradication of WPV2 in 2015. The last case of WPV3 was detected in northern Nigeria in 2012. Since then, the strength and reach of the eradication programme’s global surveillance system has been critical to verify that this strain is truly gone. Investments in skilled workers, innovative tools and a global network of laboratories have helped determine that no WPV3 exists anywhere in the world, apart from specimens locked in secure containment.

Now wild poliovirus type 1 remains in circulation in just two countries: Afghanistan and Pakistan.

What is Global Polio Eradication Initiative ?

The Global Polio Eradication Initiative (GPEI) is a public-private global effort made up of national governments, partners including the World Health Organization, Rotary International, the US Centers for Disease Control and Prevention, UNICEF, the Bill & Melinda Gates Foundation and a broad range of long-term supporters. (WHO)

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